This invention relates to a security barrier for a vessel, and in particular to a barrier which helps to prevent stowaways and other unwanted persons from boarding a vessel.

The owners and operators of larger ocean-going vessels, such as cargo ships and container ships, frequently encounter problems with stowaways. Stowaways are sometimes able to bypass port security and to board a vessel from the quayside along which the vessel is berthed. Depending upon the level of the vessel's main deck relative to the quayside (which will depend on vessel size and tide level, for example), a stowaway may be able to jump or scramble across the gap between the quayside and the vessel, over the hand rail and onto the deck of the vessel. A stowaway can then secrete him/herself in a store, lifeboat or other area on the vessel, in the hope that they can remain undiscovered when the vessel departs.

While stowaways may generally attempt to gain access to a vessel from a quayside, stowaways could also attempt to access a vessel while the vessel is at anchor in a coastal area awaiting port entry (e.g. from another vessel which is close by), or even in transit from port to port, for example in the Mediterranean.

It is an object of the present invention to provide a security barrier which prevents or hinders stowaways from gaining access to vessels.

Accordingly, one aspect of the present invention provides a barrier installed on a generally upright structure, the structure being generally elongate and protruding from a surface to rise to a first height above the surface, wherein: the barrier has a front surface, which lies on a first side of the upright structure, and a rear surface, which lies either on the same side, or on the opposite side, of the upright structure, the front and rear surfaces being connected to each other; the barrier rises to a second height above the surface, the second height being higher than the first height; and neither of the front and rear surfaces of the barrier significantly protrudes in a direction which is generally perpendicular to the plane of the upright structure than the other of the front and rear surfaces of the barrier. Advantageously, the front and/or rear surface of the barrier is attached to the upright structure.

Preferably, both the front and rear surfaces of the barrier rest on, or lie close to, the surface from which the generally upright structure protrudes.

Conveniently, the front or rear surface of the barrier terminates at a free end which is positioned at a distance above the surface from which the generally upright structure protrudes. Advantageously, the front surface terminates at a free end which is positioned above the surface from which the generally upright structure protrudes, and the barrier further comprises an infill panel which extends between the surface and the lower edge of the front surface. Preferably, in the region of the barrier above the top of the upright structure, the front and rear surfaces of the barrier are attached to one another.

Conveniently, the connection between the front and rear surfaces comprises a region of one of the one or more flexible panels which is curved through an angle. Advantageously, at least the front surface of the barrier is substantially smooth, and does not present any protruding features.

Preferably, the barrier does not comprise a significant overhang on either side of the upright structure.

Conveniently, the upright structure is a rail structure, comprising at least one elongate rail running generally parallel with the surface from which the upright structure protrudes.

Advantageously, the rail structure is a guard rail on the deck of a vessel.

Another aspect of the invention provides a barrier installed on a generally upright structure, the structure being generally elongate and protruding from a surface to rise to a first height above the surface, wherein: the barrier is formed from a sheet of material which lies on a first side of the upright structure; the barrier rises to a second height above the surface, the second height being higher than the first height; and the barrier does not significantly protrudes in a direction which is generally perpendicular to the plane of the upright structure more in one direction that the other.

Preferably, the sheet of material from which the barrier is formed is arranged to be generally planar, and parallel or substantially parallel with the upright structure.

Conveniently, the second height is at least 125% of the first height, and is more preferably at least 150% of the first height.

Advantageously, the barrier further comprises a support element, which is attached to the upright structure and protrudes above the first height, and provides support to the barrier. Preferably, the barrier is formed from one or more sheets of flexible material.

Conveniently, at least one of the sheets of material from which the barrier is formed may be arranged to adopt a flat or substantially flat configuration without damaging the sheet, and preferably wherein all of the sheets of material from which the barrier is formed may be arranged to adopt a flat or substantially flat configuration without damaging the sheet. Advantageously, at least one of the one or more sheets of material has score lines or other features formed therein to cause the sheet to bend preferentially at one or more predetermined locations.

A further aspect of the invention provides a series of barriers, each according to any of the above, attached side-by-side along the upright structure.

Preferably, the edges of each barrier touch, or lie near, the edges of adjacent barriers. Conveniently, at least one of the barriers comprises a region which overlaps with an adjacent barrier.

Advantageously, the barrier and the adjacent barrier are attached to each other in the region of the overlap.

Another aspect of the invention provides a method of installing a barrier on an upright structure, which is elongate and rises to a first height above a surface from which the upright structure protrudes, the method comprising the steps of: providing a barrier having a front surface and a rear surface, the front and rear surfaces being connected to each other; and attaching the barrier to the upright structure, so that the first surface of the barrier lies on a first side of the upright structure and the second surface of the barrier lies either on the same side, or on the opposite side, of the upright structure, so that the barrier rises to a second height above the surface, the second height being higher than the first height, and so that neither of the front and rear surfaces of the barrier significantly protrudes in a direction which is generally perpendicular to the plane of the upright structure than the other of the front and rear surfaces of the barrier.

Preferably, the barrier comprises one or more sheets of flexible material, and the method further comprising the steps of: removing the barrier from the upright structure; and attaching at least one of the one or more sheets of flexible material to the upright structure to form an alternative barrier, which protrudes in a direction which is generally perpendicular to the plane of the upright structure significantly more on one side of the upright structure than on the other.

Conveniently, the barrier comprises one or more sheets of flexible material, and the method further comprising the steps of: removing the barrier from the upright structure; and arranging the or each sheet of flexible material adopt a flat or substantially flat configuration.

A further aspect of the present invention provides a method of installing a barrier on an upright structure, which is elongate and rises to a first height above a surface from which the upright structure protrudes, the method comprising the steps of: providing a barrier which is formed from a sheet of material; and positioning the sheet of material on a first side of the upright structure, such that the barrier rises to a second height above the surface, the second height being higher than the first height, and the barrier does not significantly protrudes in a direction which is generally perpendicular to the plane of the upright structure more in one direction that the other. Advantageously, the method further comprises the steps of: removing the sheet of material from the upright structure; and arranging the sheet of flexible material adopt a flat or substantially flat configuration. In order that the invention may be more readily understood, embodiments thereof will now be described by way of example, with reference to the accompanying figures, in which:

Figures 1 and 2 show a first barrier embodying the present invention;

Figures 3 and 4 show additional features of the barrier of figures 1 and 2;

Figure 5 shows a second barrier embodying the present invention; Figure 6 shows a third barrier embodying the present invention; and

Figure 7 shows a known type of barrier having an overhang.

Turning firstly to figures 1 and 2, perspective and side elevation views are shown of a first barrier 1 embodying the present invention.

The first barrier 1 is shown in place on the deck 2 of a ship. As is common for larger vessels such as cargo vessels, the deck 2 has a short upstanding plate (sometimes known as the 'fish plate') 3 which is set at a short distance away from the outer edge 4 of the deck 2.

Positioned along the edge of the deck 2, shortly behind the fish plate 3, is a guard rail 5. The guard rail 5 comprises a top rail 6, and (in this embodiment) first and second lower rails 7, 8 with the first lower rail 7 being positioned above the second lower rail 8. The guard rail 5 further has upright supports or stanchions 9, which rise vertically or substantially vertically from the deck 2 and are connected to the rails 6, 7, 8. On a typical guard rail the stanchions 9 are provided at spaced- apart, regular intervals.

The first barrier 1 has a front surface 10, which is generally planar and positioned on the outboard side of the guard rail 5. A lower edge 1 1 of the front surface 10 rests on, or lies near, the surface of the deck 2, and in the embodiment shown is positioned behind the fish plate 3.

The front surface 10 rises to a height which is significantly above that of the top rail 6 of the guard rail 5. The guard rails on a cargo vessel may, for instance, have a height of 1 .2 m above the level of the deck. In preferred embodiments, the top part of the barrier 1 is at a height above the surface of the deck 2 which is at least 125%, or at least 150%, or more than 250%, of the height of the top rail 6 of the guard rail 5 above the surface of the deck 2.

At the top of the front surface 10 there is a transition region 12, in which the material forming the barrier curves rearwardly (i.e. in the inboard direction, relative to the vessel) and downwardly, to join a rear surface 13. The rear surface 13 is preferably parallel with the front surface 10, and extends behind (i.e. on an inboard side of) the guard rail 5. The rear surface 13 preferably extends to rest on, or lie close to, the surface of the deck 2. In preferred embodiments, the width of the front surface 10 is equal, or substantially equal, to that of the rear surface 13. Preferably, the width of the transition region 12 is also equal to, or substantially equal to, that of both the front and rear surfaces 10, 13. The barrier 1 is preferably formed from a robust, flexible material, such as a plastics material. In preferred embodiments the barrier 1 is formed from a single sheet of material, which may be generally elongate and of constant or substantially constant width along its length. The sheet of material may be positioned so that one end thereof rests on the surface of the deck 2, either inboard or outboard of the guard rail 5, and the sheet may then be attached to the guard rail 5 (described in more detail below). The sheet may then be bent and/or folded through around 180° to form the transition region 12. The other end of the sheet will then lie on the other side of the guard rail 5, and can be attached or secured to the guard rail 5 to form the completed barrier 1 .

The barrier 1 may be attached to the guard rail 5 by any suitable means. For instance, as shown in figures 1 and 2, a pair of spaced-apart looped straps may be provided to attach the barrier 1 to the top rail 6. On the front and rear surfaces 10, 13, respective upper and lower attachment holes 14, 15 may be formed, with each upper attachment hole 14 being directly or substantially directly above the lower attachment hole 15 (i.e. generally aligned therewith in the longitudinal direction of the sheet of material that forms the barrier 1 ). Straps 16 may then be passed through the attachment holes 14, 15 formed in the front and rear surfaces 10,13, so that each strap 16 passes (for example) from a rear (i.e. inboard) side of the barrier 1 , through both of the lower attachment holes 15 to the front (i.e. outboard) side thereof, and then back through the upper attachment holes 14 to the rear side of the barrier 1 , before being attached to itself at the rear side using a buckle, ratchet connector, or any other suitable means, to form a closed loop.

Similar attachments may be applied to attach the barrier 1 to either or both of the first and second lower rails 7, 8. The skilled reader will appreciate that there are many different ways in which the barrier 1 may be attached to the guard rail 5, and the invention is not limited to the use of loop straps or the like. The attachment of the barrier 1 to one or more of the rails 6,7, 8 of the guard rail 5 helps to keep the barrier 1 in place, and to prevent it from being lifted upwardly off the guard rail 5. In addition, the barrier 1 shown in figures 1 and 2 is formed from bending/folding a sheet of flexible and resilient material at the transition region 12. If it is not retained in this shape, the sheet of material will resume its original, generally flat shape. Attaching the front and rear surfaces 10, 13 of the barrier 1 to each other helps to ensure that the barrier 1 remains in the desired shape.

The sheet of material from which the barrier 1 is formed may be provided with one or more score lines, or other features, which allow the sheet to bend preferentially in the region of the score lines. The score lines may be positioned so that the sheet may bend relatively easily to form the intended shape for the barrier 1 . The score lines may, in preferred embodiments, be formed across the entire width of the sheet of material, and may be formed on the outer side, the inner side, or on both sides.

The skilled reader will appreciate that alternative features, other than score lines, may be used to allow the barrier to bend preferentially at desired points. In some embodiments, no score lines or other features of this kind are provided.

It will be understood that the barrier 1 shown in figures 1 and 2 provides a barrier which will make it significantly more difficult for a potential stowaway to gain access to the vessel. The front surface 10 of the barrier 1 is taller than the guard rail 6, and is preferably of a height which will be very difficult for most individuals to scale. In embodiments of the invention the total height of the barrier above the deck 2 may be 2.5m, or even higher. Moreover, at least the front surface of the barrier 1 is preferably continuous (i.e. including no significant protrusions, dents, holes or other similar features) and formed from a smooth material presenting no external features which may be used as hand or foot holds, and the transition region 12 preferably comprises a smoothly curved portion of this material, which will be extremely difficult to climb over.

While the barrier 1 is shown in isolation in figure 1 for the purposes of clarity, it is envisaged that in use a series of barriers 1 will be provided side-by-side, with their edges touching one another, so as to provide an effectively continuous barrier passing along the length of the guard rail 5. Barriers can be provided around the perimeter of a vessel, on one or more decks, to provide a barrier that hinders or prevents stowaways from gaining access to the vessel at all places around the vessel, which may otherwise allow stowaways to access the vessel relatively easily.

In preferred embodiments, the front and rear surfaces 10, 13 of the barrier 1 are attached to each other above the level of the top rail 6 of the guard rail 5. This is in order to maintain the desired shape of the barrier 1 , and to prevent the front and rear surfaces 10, 13 from spreading too far apart from one another, due to the elastic nature of the material from which the barrier 1 is formed.

As shown in figure 3, this attachment may take the form of further looped straps 17, which are threaded between the front and rear surfaces 10, 13 of the barrier 1 in a similar manner to the looped straps 16, described above, which attach the barrier 1 to the top rail 6. The further looped straps 17 pass through respective upper and lower attachment holes 18, 19, which are formed in both the front and rear surfaces 10, 13 of the barrier 1 , and may be tightened to draw the front and rear surfaces 10, 13 towards one another. Once again, any other suitable method of attaching the front and rear surfaces 10, 13 of the barrier 1 to each other, and preventing the surfaces 10, 13 from being above a set distance from one another, at a position above the top rail 6 of the guard rail 5, may be used.

In other embodiments, the front surface may be formed from a first sheet of material, and the rear surface may be formed from a second (separate) sheet of material, and the top parts of the first and second sheets of material may be attached together. In preferred examples of this kind of arrangement, the top parts of the first and second sheets of material may lie generally parallel to each other, and be attached together by any suitable means, for instance by looped straps and/or bolts. Embodiments of this kind may have an advantage in that the connection between the front surface and the rear surface does not comprise a bend in a resilient/elastic sheet of material, and it will therefore not be necessary to form connections, or take other measures, to prevent the barrier from bulging outwardly at its top region.

In order to maintain the desired shape for the portion of the barrier 1 that rises above the top rail 6 of the guard rail 5, it may be necessary or desirable to include a support element, which is preferably attached to one or more of the rails 6, 7, 8 of the guard rail 5, and extends upwardly above the level of the top rail 6 to provide support to the barrier 1 . A support element of this kind, in the form of a support rod 20, is shown in figure 4, which shows a side elevation view of the barrier 1 , apart from which the looped straps 16, 17 are omitted for the purposes of clarity.

The support rod 20 takes the form of a generally elongate support member, and may for instance comprise a wooden pole or metal bar. The support rod 20 is positioned on the rear (i.e. inboard) side of the guard rail 5, and is oriented generally vertically, i.e. protruding directly upwardly in a direction which is substantially perpendicular to the plane of the top surface of the deck 2.

The support rod 20 is attached, in the embodiment shown, to the top rail 6 and to the first intermediate rail 7. The support rod 20 rises above the level of the top rail 6, and in the embodiment shown extends close to the top of the transition region 12 of the barrier 1 .

The barrier 1 is placed around the support rod 20 so that, once the barrier 1 is fully installed, the support rod 20 is entirely contained within the barrier 1 .

The support rod 20 may be attached to the rail 6, 7 of the guard rail 5 by any suitable means. For instance, holes (not shown) may be formed through the support rod 20, and loop straps or ratchet ties (not shown) may pass through these holes and around the rail 6, 7 of the guard rail 5. The support rod 20 may be attached to an internal part of the barrier 1 , by any suitable means. The support rod 20 is preferably provided substantially midway along the width of the barrier 1 , i.e. generally centrally disposed within the barrier 1 . In the example shown, only one support rod 20 is provided for the barrier 1 . Where several barriers 1 are provided side-by-side, it is envisaged that one support rod 20 will be provided for each barrier 1 .

However, where required by the circumstances, two or more support rods 20 may be provided for one barrier 1 , and this may particularly be the case if the barrier 1 is relatively wide.

Alternatively, where several barriers are provided side-by-side and the barriers are attached together, it may be possible to support the barriers as a whole through the use of one support rod 20 positioned within every second barrier (for example), with intermediate barriers not having any support rods provided therein.

The skilled reader will understand that an appropriate number of support rods may be provided, depending on the requirements of any particular application.

It will be understood that the provision of a support element within the barrier 1 will greatly increase the rigidity of the barrier 1 , particularly in the region above the top rail 6 of the guard rail 5. If the barrier 1 is formed from a relatively thin material, and an individual attempts to climb over the top of the barrier, if no support element is provided then the top of the barrier may bend or otherwise deform, thus making it easier for the individual to climb over the barrier 1 . The provision of a support element, such as a support rod 20, will make such bending or deforming much less likely.

Instead of a single, generally vertical support rod, any other suitable support arrangement may be used. For instance, a pair of crossed support rods may be provided within a barrier. In the example shown in figures 1 -4, both the front and rear surfaces 10, 13 of the barrier 1 extend to the level of the deck 2.

Figure 5 shows a second barrier 21 embodying the present invention, which is similar in many respects to the first barrier 1 shown in figures 1 to 4. Once again, the looped attachment straps have been omitted from this figure for the purposes of clarity.

The front surface 10 of the barrier 21 extends to the level of the deck 2, and again rests on the deck 2, behind (i.e. inboard of) the fish plate 3. However, the rear surface 13 of the barrier 21 does not extend to the level of the deck, and terminates at a free end 22, which is significantly above the level of the deck 2. In the embodiment shown, the free end 22 is below the first intermediate rail 7, but above the second intermediate rail 8. The rear surface 13 may therefore be attached both to the top rail 6 and to the first intermediate rail 7. However, the fact that the rear surface 13 does not extend to the surface of the deck 2 means that overall the barrier 21 is formed from a shorter length of material, and is therefore lighter, easier to transport and store, and cheaper to manufacture. Crucially, the front surface 10, which is the surface faced by a potential stowaway, still occupies the entire height of the barrier 21 . The fact that the rear surface 13 does not extend to deck level will not greatly affect the strength or any other aspect of the performance of the barrier 21 .

Turning to figure 6, a third barrier 23 embodying the present invention is shown. As with the second barrier 21 , the rear surface 13 of the barrier 23 terminates at an end point 22 which is above the level of the deck 2, and in this case lies between the first and second intermediate rails 7, 8.

However, with this third barrier 23, the front surface 10 of the barrier 23 also terminates at a free end 24 which is above the level of the deck 2. In the example shown, this free end 24 lies between the second intermediate rail 8 (i.e. the lowest rail of the guard rail 5) and the deck 2 itself. Preferably, the free end 24 lies, when barrier 23 is fully installed, closer to the level of the second intermediate rail 8 than the level of the deck 2.

To avoid presenting a gap through which a stowaway may be able to fit in order to gain access to the vessel, an infill panel 25 extends between the free end 24 at the lower edge of the front surface 10 of the barrier 23 and the surface of the deck 2. The infill panel 25 is preferably provided on the rear (i.e. inboard) side of the front surface 10 of the barrier 23, and extends above the level of the free end 24 thereof. The region where the front surface 10 of the barrier 23 and the infill panel 25 overlap therefore does not present any useful grip or handhold/toehold.

The infill panel 25 may be attached to the second intermediate rail 8 and/or to the front side 10 of the barrier 23, for instance through looped straps as discussed above, and the skilled person will realise that there are many ways in which this may be achieved.

Installing the barrier 23 in this manner allows the maximum possible height of the barrier 23, given the overall length of the sheet of material from which the barrier 23 is formed.

Providing a barrier which is formed from a shorter length of material confers advantages, as discussed above, in that the barrier is smaller, lighter and cheaper to produce. It will also be necessary, at certain times, to remove the barriers from around the perimeter of the vessel and to store the barriers awaiting subsequent use. The barriers may be stored, for instance, in boxes or containers provided on the vessel, either above or below the main deck of the vessel. If the barriers are formed from sheets of material which are shorter, this will make storage (and transportation) of the barriers significantly more convenient.

In the embodiments described above, the main part of the barrier is formed from a single, unbroken and unitary sheet of material. However, the barrier may be formed from two or more sheets of material which are joined together. For instance, the front part 10 and the transition region 12 may be formed from a first sheet of material, and the back part 13 may be formed from a second, separate sheet of material. The two sheets of material are preferably removably attachable to one another, for instance by loop straps, studs, rivets, nuts and bolts, or any other suitable means. However, the two sheets of material may be permanently attached to each other (i.e. attached in such a way that separation of the sheets will lead to damage of one or both sheets).

The skilled reader will appreciate that formation of the barrier from two more sheets of material will greatly ease storage and transportation of the barrier.

Several designs of barrier have been proposed which include a significant overhang on the outboard side of the guard rail, to prevent boarders from climbing up and over the barrier from a starting position beneath the level of the barrier. Examples of such overhanging barriers can be seen in WO 2013/072704 and WO 2016/102929.

By contrast, barriers disclosed herein generally do not comprise a significant overhang on the outboard side of the barrier. Rather, the barriers disclosed herein have a generally planar configuration, rising vertically (or substantially vertically) with respect to the deck of a vessel on both the front and rear sides.

As can be seen in the illustrations, in the transition region 12 of the barriers, where the barriers are curved through around 180°, the material from which the barrier is formed will generally bulge outwardly, in both the inboard and outboard directions. However, this does not constitute an overhang, as appears in the examples mentioned above. An overhang, in this context, is a part of the barrier, which is generally bulbous and/or smooth in cross-sectional shape, which extends significantly outwardly, in the outboard direction, generally by at least 0.5m or 1 m. Barriers having an overhang are generally significantly asymmetric, having a laterally-extending overhang on the outboard side, and no corresponding feature on the inboard side.

By contrast, the barriers disclosed herein will generally not extend laterally more on the outboard side than on the inboard side. Any lateral extension of the barrier at or around the transition region 12 will generally arise from the properties of the material from which the barrier is made, i.e. this material cannot, without sustaining permanent damage be bent or folded through a sharp turn. When installed, barriers embodying the present invention may be generally symmetrical in shape, about a plane, containing (or lying parallel with) a guard rail on which the barrier is installed.

Embodiments of the invention provide a barrier which can be placed, at the choice of an operator, either in an overhang-type configuration, or in a configuration as described above, which is more suitable for preventing stowaways from gaining access to the vessel when the vessel is anchored at a quayside. Figure 7 shows a schematic view of a known overhang-type barrier 26, which is formed from a single sheet 27 of material. At a lower end 28, the sheet rests on the deck 2, in front of the fish plate 3. The sheet 27 extends upwardly, passing in front of the second intermediate rail 8, and then behind the first intermediate rail 7 and the top rail 6.

The sheet 27 then curves in an outboard direction, to form a bulbous overhang 29, and the upper free end 30 of the sheet 27 passes under the first intermediate rail 7 to meet a middle part of the sheet 27, and form a closed loop, in the region of the first intermediate rail 7. The single sheet 27 therefore generally forms a P-shape, in cross-section, including a bulbous overhang on the outboard side.

The single sheet 27 may be held in place, and attached to the rails 6,7, 8 of the guard rail 5, and also be connected to itself, in the region of the upper free end 30, by looped straps, or any other suitable means. It is envisaged that a barrier 26 of this kind may be removed from the guard rail 5, and the single sheet 27 may then be arranged and bent/folded in a different manner, to form a barrier 1 , 21 , 23 of any of the types discussed above. The sheet 27 may have attachment holes formed therein which allow looped straps or the like to be used to hold the sheet 27 in place to form the overhang-type barrier 26. When the sheet 27 is formed into a barrier without an overhang, of the type discussed above, the same attachment holes may be used to hold the barrier in place in this configuration. Alternatively, at least some of the attachment holes formed through the sheet 27 may be used in only one or the other of the configurations.

The above description states that a series of barriers may be placed side-by- side along the guardrail of a vessel (or along an alternative upright structure), with the edges of each barrier lying beside, or touching, the edges of the adjacent barriers. However, it is also envisaged that adjacent barriers may have a region of overlap. In these embodiments, adjacent barriers may be attached to one another, at the region of overlap, to increase the stiffness, strength and/or integrity of the series of barriers as a whole. For example, where the barriers are each formed from a single sheet of material, the sheet may have a protruding section, which is wider than the remainder of the sheet. This protruding section may be arranged to lie, when the barrier is installed, as part of the rear surface of each barrier (although the protruding section may be arranged to lie on the front surface, or on both the front and rear surfaces). The protruding section may be provided on one side only of the sheet of material. When a series of barriers are installed together side-by-side, the protruding section of each barrier may extend to overlap part of an adjacent barrier. Where each barrier is formed from two or more sheets of material, one sheet of material may be wider than the others, and the additional width of this sheet may provide a protrusion which extends to overlap part of an adjacent barrier. If each barrier comprises a first sheet of material which primarily forms the rear surface, and a second sheet of material which primarily forms the front surface, the first sheet of material is preferably wider than the second sheet of material (although this need not be the case).

The protruding section may be attached to the adjacent barrier, for instance by looped straps, bolts, or any other suitable means. The skilled reader will understand how this will strengthen the installation of barriers, help to maintain adjacent barriers in correct alignment with each other, and reduce the risk of gaps appearing between barriers that might provide a handhold/foothold or attachment point.

The barriers described above have a front surface and a rear surface, which are connected to each other. It is also envisaged that barriers embodying the present invention may comprise a single sheet of material, which is arranged on the front (i.e. outboard) side of the guardrail, and simply protrudes upwardly, terminating at a free end at the top thereof. The single sheet of material may be generally planar, i.e. not significantly curved or bent. In preferred embodiments no further sheet of material is provided to form a rear surface or the like.

The single sheet of material may be attached to the guardrail by any convenient means, e.g. by looped straps.

It is envisaged that a barrier formed from a single sheet of material will require reinforcement if it is to maintain an appropriate shape, particularly if significant external forces act on the sheet, e.g. arising from a person attempting to climb over the barrier. A support element (e.g. as described above, and illustrated in figure 4) may be used to support the barrier and to maintain the shape of the barrier. Alternatively, or in addition, barriers of this kind may be installed in a series along the guardrail, and may overlap each other to provide reinforcement to each other. It will be understood that installing barriers of this kind such that they overlap each other will be relatively straightforward. The sheet of material that comprises each barrier may be formed with, for examples, attachment holes at its side regions, so that the sides of adjacent barriers may be easily attached together by way of looped straps, bolts, or any other suitable means.

The skilled reader will appreciate that the barriers disclosed herein will be useful in many applications, in particular where stowaways or other unwanted boarders may attempt to get access to a vessel from a height which is roughly level with the deck of the vessel.

In the discussion above, the barriers are disclosed as being provided on guard rails, including a series of spaced-apart, horizontal rails. However, it is envisaged that barriers may be attached to other generally upright structures, such as fences or solid walls, which may be located on land, rather than at sea. For instance, barriers of the type discussed above may be installed along the length of a fence to reduce the likelihood of an unauthorized person being able to cross the fence.

In the discussion above, the barriers have a front surface, which is positioned on the outboard side of a guardrail, and a rear surface, which is positioned on the inboard side of the guardrail. However, in other embodiments both the front and rear surfaces may be positioned on the outboard side of the guardrail. In these embodiments, it is envisaged that the rear surface (and optionally also the front surface) of the barrier will be attached to the guardrail, and from the discussion above the skilled reader will understand how this may be achieved. Where the barrier is to be installed on a wall or other generally solid upright structure, the barrier may need to be attached to the wall by way of one or more fixtures provided on the wall, for instance one or more metal loops which are sunk or drilled into the wall.

An advantageous feature of the barriers described above is that the barriers are formed from one or more sheets of material, each of which, when not in use, can adopt a flat or substantially flat configuration (i.e. arranged so that the all or substantially all of the sheet generally lies in the same plane). This will make storage and transportation of the barrier significantly easier. As discussed above, when not in use the sheet(s) of material that make up a barrier might be stored in containers or other storage units, and when used in connection with a maritime vessel these units may be positioned either below or above deck. Since the sheets of material can be laid flat or substantially flat, they can be easily stacked or otherwise arranged in a manner that uses space efficiently. The skilled reader will understand that this will not be possible with barriers that are formed to have a permanent curved, bulbous or otherwise non-flat shape, and such barriers can make far less efficient use of space when in storage or being transported.

When used in this specification and claims, the terms "comprises" and "comprising" and variations thereof mean that the specified features, steps or integers are included. The terms are not to be interpreted to exclude the presence of other features, steps or components.

The features disclosed in the foregoing description, or the following claims, or the accompanying drawings, expressed in their specific forms or in terms of a means for performing the disclosed function, or a method or process for attaining the disclosed result, as appropriate, may, separately, or in any combination of such features, be utilised for realising the invention in diverse forms thereof.